Magnetic elements of amorphous based dual free layer structures and recording devices using such elements

ABSTRACT

A magnetic element includes a first free layer, a barrier layer over the first free layer, and a second free layer over the barrier layer. The first free layer includes a first ferromagnetic bilayer and a first amorphous insertion layer (e.g., CoHf) between the first ferromagnetic bilayer. The first ferromagnetic bilayer is selected from CoB, CoFeB, FeB, and combinations thereof. The second free layer includes a second ferromagnetic bilayer and a second amorphous insertion layer (e.g., CoHf) between the second ferromagnetic bilayer. The second ferromagnetic bilayer is selected from CoB, CoFeB, FeB, and combinations thereof. Each of the first and the second amorphous insertion layer independently can be ferromagnetic or non-ferromagnetic and can have a recrystallization temperature of about 300° C. and above. The magnetic element can further include a non-ferromagnetic amorphous buffer layer and/or a non-ferromagnetic amorphous capping layer. The magnetic element can further include a ferromagnetic amorphous seed layer.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.17/185,797, filed Feb. 25, 2021, now U.S. Pat. No. 11,430,592, whichapplication claims benefit of U.S. Provisional Patent Application Ser.No. 63/082,772, filed Sep. 24, 2020, each of which is hereinincorporated by reference.

BACKGROUND OF THE DISCLOSURE Field of the Disclosure

Embodiments of the present disclosure generally relate to magneticelements of dual free layer structures enhanced thermal-mechanically andmagnetically with amorphous multilayer structures and recording devicesusing such elements, such as a read sensor of a read head of a datastorage device.

Description of the Related Art

The heart of the functioning and capability of a computer is the storingand writing of data to a data storage device, such as a hard disk drive(HDD). The volume of data processed by a computer is increasing rapidly.There is a need for higher recording density of a magnetic recordingmedium to increase the function and the capability of a computer.

In order to achieve higher recording densities, such as recordingdensities exceeding 2 Tbit/in² for a magnetic recording medium, thewidth and pitch of write tracks are narrowed, and thus the correspondingmagnetically recorded bits encoded in each write track are narrowed.Attempts to achieve increasing requirements of advanced narrow gapreader sensors of read heads to achieve reading of higher recordingdensities have proposed utilizing tunnel magnetoresistive (TMR) readersensors with free layers of transition metal Co/Fe alloys containingamorphous elements of Ta, CoFeB, or CoFeBTa. In addition, those readersensors have been fabricated using conventional single free layers witha special set of pinning structures having antiferromagnetic (AFM)layers for self-exchange bias. Consequently, those reader sensors maysuffer in process, device performance, and areal recording densityenhancement due to the degraded magnetic pinning layer properties,thermal stability, and the disturbed exchange bias of the AFM layers.

SUMMARY OF THE DISCLOSURE

Embodiments of the present disclosure generally relate to magneticelements with amorphous layers in dual free layer structures andrecording devices using such elements, such as a read sensor of a readhead of a data storage device. These amorphous layers haverecrystallization temperatures of about 300° C. and above.

In one embodiment, a magnetic element includes a first free layer, abarrier layer, and a second free layer. The first free layer includes afirst ferromagnetic bilayer selected from CoB, CoFeB, FeB, andcombinations thereof and a first amorphous insertion layer between thefirst ferromagnetic bilayer. The barrier layer is over the first freelayer. The second free layer is over the barrier layer. The second freelayer includes a second ferromagnetic bilayer selected from CoB, CoFeB,FeB, and combinations thereof and a second amorphous insertion layerbetween the second ferromagnetic bilayer. Each of the first and secondamorphous insertion layers independently has a recrystallizationtemperature of about 300° C. and above.

In another embodiment, a magnetic element includes a buffer layer, afirst free layer, a barrier layer, a second free layer, and a cappinglayer. The buffer layer includes a first non-ferromagnetic layer. Thefirst free layer is over the buffer layer. The first free layer includesa first ferromagnetic bilayer selected from CoB, CoFeB, FeB, andcombinations thereof and a first amorphous insertion layer between thefirst ferromagnetic bilayer. The barrier layer is over the first freelayer. The second free layer is over the barrier layer. The second freelayer includes a second ferromagnetic bilayer selected from CoB, CoFeB,FeB, and combinations thereof; and a second amorphous insertion layerbetween the second ferromagnetic bilayer. The capping layer is over thesecond free layer. The capping layer includes a second non-ferromagneticlayer. Each of the first and second amorphous insertion layersindependently has a recrystallization temperature of about 300° C. andabove.

In still another embodiment, a magnetic element includes a ferromagneticseed layer, a non-ferromagnetic buffer layer, a first free layer, abarrier layer, a second free layer, and a capping layer. Thenon-ferromagnetic buffer layer is over the ferromagnetic seed layer. Thefirst free layer is over the buffer layer. The first free layer includesa first ferromagnetic bilayer selected from CoB, CoFeB, FeB, andcombinations thereof and a first amorphous insertion layer between thefirst ferromagnetic bilayer. The barrier layer is over the first freelayer. The second free layer is over the barrier layer. The second freelayer includes a second ferromagnetic bilayer selected from CoB, CoFeB,FeB, and combinations thereof and a second amorphous insertion layerbetween the second ferromagnetic bilayer. The capping layer is over thesecond free layer. The capping layer includes a non-ferromagnetic layer.Each of the first and second amorphous insertion layers independentlyhas a recrystallization temperatures of about 300° C. and above.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentdisclosure can be understood in detail, a more particular description ofthe disclosure, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this disclosure and are therefore not to beconsidered limiting of its scope, for the disclosure may admit to otherequally effective embodiments.

FIG. 1 is a schematic illustration of certain embodiments of a magneticmedia drive including a magnetic read head.

FIG. 2 is a schematic illustration of certain embodiments of a crosssectional side view of a head assembly facing a magnetic storage medium.

FIGS. 3-5 are schematic illustrations of different embodiments of amagnetic element from an MFS view.

FIG. 6 is a schematic illustration of a perspective view of certainembodiments of a read sensor including a magnetic element.

FIG. 7 is a chart of the coercivity Hc of samples of various free layerstacks or film layers after a series of rapid thermal annealing.

FIG. 8 is a chart of magnetic moment and magnetostriction in amorphousCoHf films as a function of Hf content in atomic percent.

FIGS. 9A-9B are charts of the effective magnetic moment and the dampingconstant of various samples were measured by FMR.

FIGS. 10A-10B are charts of the device TMR ratio, magnetic moment Mst,and coercivity Hc of various dual free layers.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements disclosed in oneembodiment may be beneficially utilized on other embodiments withoutspecific recitation.

DETAILED DESCRIPTION

In the following, reference is made to embodiments of the disclosure.However, it should be understood that the disclosure is not limited tospecific described embodiments. Instead, any combination of thefollowing features and elements, whether related to differentembodiments or not, is contemplated to implement and practice thedisclosure. Furthermore, although embodiments of the disclosure mayachieve advantages over other possible solutions and/or over the priorart, whether or not a particular advantage is achieved by a givenembodiment is not limiting of the disclosure. Thus, the followingaspects, features, embodiments and advantages are merely illustrativeand are not considered elements or limitations of the appended claimsexcept where explicitly recited in a claim(s). Likewise, reference to“the disclosure” shall not be construed as a generalization of anyinventive subject matter disclosed herein and shall not be considered tobe an element or limitation of the appended claims except whereexplicitly recited in a claim(s). Usage in the Summary of the Disclosureor in the Detailed Description of the term “comprising” shall meancomprising, consisting essentially, and/or consisting of.

The term “recrystallization temperature” for a ferromagnetic layer asused herein can be determined as follows: (1) deposit a single magneticamorphous layer to a thickness of, e.g., 5-10 nm, over a siliconsubstrate, (2) short anneal the layer for a period of time (e.g., oneminute) at a preset temperature and then cool down, (3) measure magneticproperties of the annealed layer, (4) repeat this experimental procedure(1)-(3) at any different elevated temperatures of interest. Thetemperature in which the amorphous film has shown at a change incoercivity (10%) is deemed the recrystallization temperature.

The term “recrystallization temperature” for a non-ferromagnetic layeras used herein is determined by energy release on heating indifferential scanning calorimetry (DSC) or by the change of resistivityon measuring the sheet resistance.

Embodiments of the present disclosure generally relate to magneticelements with amorphous layers (e.g., cobalt hafnium (CoHf)) in dualfree layer structures and recording devices using such elements, such asa read sensor of a read head of a data storage device. These amorphouslayers have high recrystallization temperatures of about 300° C. andabove.

In certain embodiments, ferromagnetic amorphous insertion layers (e.g.,CoHf) between bilayer free layers (FLs) of dual free layer (DFL) readersensors provide higher magnetic moment (Mst) and TMR signal. In certainaspects, higher magnetic moment and TMR signal are provided without anincrease both in coercivity and in magnetostriction. Overall loweredcoercivity and magnetostriction contribute to and yield increasedprocess controllability, sensor stabilization, low noise and higher SNR.

In certain embodiments, non-ferromagnetic amorphous insertion layers(e.g., CoHf) between bilayer free layers (FLs) of dual free layer (DFL)reader sensors provide higher TMR signal. The non-ferromagneticamorphous insertion layers have high-quality and smooth interfaces withthe film layers of the magnetic elements providing a higher TMR signal.

In certain embodiments, a non-ferromagnetic amorphous buffer layer(e.g., CoHf) and/or a non-ferromagnetic amorphous capping layer (e.g.,CoHf) has a high quality/smooth interface for interfacing with the filmlayers of the magnetic elements providing a higher TMR signal.

In certain embodiments, a ferromagnetic amorphous seed layer (e.g.,CoHf) has a high-quality and smooth interface for interfacing with thefilm layers of the magnetic elements providing a higher TMR signal.

In certain embodiments as described herein, a higher TMR signalcontributes to a larger signal amplitude and/or high signal-to-noiseratio (SNR). In certain embodiments as described herein, an amorphouslayer (e.g., CoHf) or has a high recrystallization temperature providingincreased thermal stability to the magnetic elements. In certain aspectsof certain embodiments, the amorphous layer(s) (e.g., CoHf) provides ahigh-quality and smooth interface increasing robustness of the magneticelements. The increased thermal stability and/or the increasedrobustness provides reduced process corrosion and/or reduceddelamination which contributes to low noise, increased SNR, and highprocess yield.

FIG. 1 is a schematic illustration of certain embodiments of a magneticmedia drive 100 including a magnetic write head and a magnetic readhead. The magnetic media drive 100 may be a single drive/device orcomprise multiple drives/devices. The magnetic media drive 100 includesa magnetic recording medium, such as one or more rotatable magnetic disk112 supported on a spindle 114 and rotated by a drive motor 118. For theease of illustration, a single disk drive is shown according to oneembodiment. The magnetic recording on each magnetic disk 112 is in theform of any suitable patterns of data tracks, such as annular patternsof concentric data tracks (not shown) on the magnetic disk 112.

It is to be understood that the magnetic recording head discussed hereinis applicable to a data storage device such as a hard disk drive (HDD)as well as a tape drive such as a tape embedded drive (TED) or aninsertable tape media drive. An example TED is described in co-pendingpatent application titled “Tape Embedded Drive,” U.S. application Ser.No. 16/365,034, filed Mar. 31, 2019, assigned to the same assignee ofthis application, which is hereby incorporated by reference. As such,any reference in the detailed description to a HDD or tape drive ismerely for exemplification purposes and is not intended to limit thedisclosure unless explicitly claimed. Furthermore, reference to orclaims directed to magnetic recording devices are intended to includeboth HDD and tape drive unless HDD or tape drive devices are explicitlyclaimed.

It is also to be understood that aspects disclosed herein, such as themagnetoresistive devices, may be used in magnetic sensor applicationsoutside of HDD's and tape media drives such as TED's, such as spintronicdevices other than HDD's and tape media drives. As an example, aspectsdisclosed herein may be used in magnetic elements in magnetoresistiverandom-access memory (MRAM) devices (e.g., magnetic tunnel junctions aspart of memory elements), magnetic sensors or other spintronic devices.

At least one slider 113 is positioned near the magnetic disk 112. Eachslider 113 supports a head assembly 121 including one or more read/writeheads, such as a write head and such as a read head comprising amagnetic element. As the magnetic disk 112 rotates, the slider 113 movesradially in and out over the disk surface 122 so that the head assembly121 may access different tracks of the magnetic disk 112 where desireddata are written or read. Each slider 113 is attached to an actuator arm119 by way of a suspension 115. The suspension 115 provides a slightspring force which biases the slider 113 toward the disk surface 122.Each actuator arm 119 is attached to an actuator 127. The actuator 127as shown in FIG. 1 may be a voice coil motor (VCM). The VCM includes acoil movable within a fixed magnetic field, the direction and speed ofthe coil movements being controlled by the motor current signalssupplied by control unit 129.

During operation of the magnetic media drive 100, the rotation of themagnetic disk 112 generates an air or gas bearing between the slider 113and the disk surface 122 which exerts an upward force or lift on theslider 113. The air or gas bearing thus counter-balances the slightspring force of suspension 115 and supports slider 113 off and slightlyabove the disk surface 122 by a small, substantially constant spacingduring normal operation.

The various components of the magnetic media drive 100 are controlled inoperation by control signals generated by control unit 129, such asaccess control signals and internal clock signals. Typically, thecontrol unit 129 comprises logic control circuits, storage means and amicroprocessor. The control unit 129 generates control signals tocontrol various system operations such as drive motor control signals online 123 and head position and seek control signals on line 128. Thecontrol signals on line 128 provide the desired current profiles tooptimally move and position slider 113 to the desired data track on disk112. Write and read signals are communicated to and from the headassembly 121 by way of recording channel 125. Certain embodiments of amagnetic media drive of FIG. 1 may further include a plurality of media,or disks, a plurality of actuators, and/or a plurality number ofsliders.

FIG. 2 is a schematic illustration of certain embodiments of a crosssectional side view of a head assembly 200 facing the magnetic disk 112or other magnetic storage medium. The head assembly 200 may correspondto the head assembly 121 described in FIG. 1 . The head assembly 200includes a media facing surface (MFS) 212 facing the magnetic disk 112.As shown in FIG. 2 , the magnetic disk 112 relatively moves in thedirection indicated by the arrow 232 and the head assembly 200relatively moves in the direction indicated by the arrow 233.

The head assembly 200 includes a magnetic read head 211. The magneticread head 211 include a sensing element 204 disposed between shields S1and S2. The sensing element 204 and the shields S1 and S2 have a MFS 212facing the magnetic disk 112. The sensing element 204 is a magneticelement sensing the magnetic fields of the recorded bits, such asperpendicular recorded bits or longitudinal recorded bits, in themagnetic disk 112 by a TMR effect. In certain embodiments, the spacingbetween shields S1 and S2 is about 17 nm or less.

The head assembly 200 may optionally include a write head 210. The writehead 210 includes a main pole 220, a leading shield 206, and a trailingshield (TS) 240. The main pole 220 comprises a magnetic material andserves as a main electrode. Each of the main pole 220, the leadingshield 206, and the trailing shield (TS) 240 has a front portion at theMFS. The write head 210 includes a coil 218 around the main pole 220that excites the main pole 220 producing a writing magnetic field foraffecting a magnetic recording medium of the rotatable magnetic disk112. The coil 218 may be a helical structure or one or more sets ofpancake structures. The TS 240 comprises a magnetic material, serving asa return pole for the main pole 220. The leading shield 206 may provideelectromagnetic shielding and is separated from the main pole 220 by aleading gap 254.

FIG. 3 is a schematic illustration of certain embodiments a magneticelement 300, such as a magnetic element between shields S1 and S2 of themagnetic read head 211 of FIG. 2 or other magnetic read heads, from anMFS view. The magnetic element 300 comprises a dual free layer (DFL) ofa first free layer 310 and a second free layer 330 separated by abarrier layer 320, such as an insulating tunneling non-magnetic barrierlayer.

The magnetic element 300 can be fabricated by forming a seed layer 302over a lower shield S1. A buffer layer 304 is formed over the seed layer302. The first free layer 310 is formed over and proximate the bufferlayer 304. The barrier layer 320 is formed over the first free layer310. The second free layer 330 is formed over the barrier layer 320. Acapping layer 308 is formed over the second free layer 330. An uppershield S2 is formed over the capping layer 308 by etching back a part ofthe capping layer and then by contacting to the etch-backed cappinglayer.

The first free layer 310 comprises a first set of two or moreferromagnetic layers 312 and comprises a first amorphous CoHf insertionlayer 314 between the pluralities of ferromagnetic layers 312. Thesecond free layer 330 comprises a second set of two or moreferromagnetic layers 332 and comprises a second amorphous CoHf insertionlayer 334 between the pluralities of ferromagnetic layers 332.

In certain embodiments, the first amorphous insertion layer 314 of thefirst free layer 310 and the second amorphous insertion layer 334 of thesecond free layer 330 are ferromagnetic and independently comprises analloy of one or more transition metals and one or more amorphous formingelements. The transition metal is Co, Fe, Ni, other suitable transitionmetals, or combinations thereof. The amorphous forming element is Ta,Zr, Hf, W, Ti, C, P, B, Si, Nb, other suitable amorphous formingelement, or combinations thereof. The first amorphous insertion layer314 and the second amorphous insertion layer 334 independently comprisesthe one or more amorphous forming element in an atomic percent incontent from greater than 0% to less than about 30%.

In certain embodiments, the first amorphous insertion layer 314 of thefirst free layer 310 and the second amorphous insertion layer 334 of thesecond free layer 330 are non-ferromagnetic and independently comprisesone or more amorphous forming element of Ta, Zr, Hf, W, Ti, C, P, B, Si,Nb, other suitable amorphous forming elements, or combinations thereofalone, or alloys with one or more transition metals of Co, Fe, Ni, othersuitable transition metals, or combinations of transition metalsthereof. The first amorphous insertion layer 314 and the secondamorphous insertion layer 334 comprises the amorphous forming element inan atomic percent content from about 30% to about 100%.

In certain embodiments, each of the first amorphous CoHf insertion layer314 and the second amorphous CoHf insertion layer 334 independentlycomprises CoHf having an atomic percent of Hf from about 5 to about 95%in content. Each of the first and second amorphous CoHf insertion layers314, 334 comprising CoHf is independently an amorphous layer having ahigh recrystallization temperature of about 300° C. and above. The firstand second amorphous CoHf insertion layers 314, 334 respectively providethermal stability to the first free layer 310 and the second free layer330 so that the magnetic element 300 can properly operate over a widetemperature range.

In certain embodiments, each of the first amorphous CoHf insertion layer314 and the second amorphous CoHf insertion layer 334 is ferromagneticand each independently comprises CoHf having an atomic percent of Hffrom about 5 to about 30% in content. In certain embodiments, each ofthe first and second ferromagnetic amorphous CoHf insertion layers 314,334 independently has a thickness from about 0.05 nm to about 1.0 nm. Incertain embodiments, each of the first and second magnetic amorphousCoHf insertion layers 314, 334 independently has a magnetic moment fromabout 200 to about 1000 emu/cm³. The ferromagnetic amorphous CoHfinsertion layers 314, 334 increase the magnetic moment (Mst) of each ofthe respective free layers 310, 330 and thus contribute to a higher TMRsignal for the DFL in comparison to those without such amorphousinsertion layers. The ferromagnetic amorphous CoHf insertion layers 314,334 increase the magnetic moment of each of the respective free layers310, 330 without increasing the coercivity and the magnetostriction ofthe free layer. The amorphous CoHf insertion layer based reader sensorstructures in addition have increased adhesion and/or increasedthermally stability with reduced corrosion and delamination during postoperational processes providing increased reliability of devices. Incertain aspects, the low magnetostriction of the amorphous CoHfinsertion layers 314, 334 and the DFL with such insertion layers reducesthe noise in part of the TMR signal, providing a higher signal-to-noiseratio (SNR) in comparison to those without amorphous CoHf insertionlayers. In certain embodiments, the free layer 310 is formed to have amagnetostriction of less than about 5.0 ppm and the core part of DFLreader sensor, including the free layer 310, barrier 320 and the freelayer 330, is formed to have an overall magnetostriction of less thanabout 5.0 ppm.

In certain embodiments, each of the first amorphous CoHf insertion layer314 and the second amorphous CoHf insertion layer 334 isnon-ferromagnetic and independently comprises CoHf having an atomicpercent of Hf from more than about 30 to about 95% in content. Incertain embodiments, each of the first and second non-ferromagneticamorphous CoHf insertion layers 314, 334 independently has a thicknessfrom about 0.5 nm or less. In order to control the magnetic moment (Mst)of each of the respective free layers 310, 330, the non-magneticamorphous CoHf insertion layers 314, 334 are formed thinner incomparison to ferromagnetic amorphous CoHf insertion layers 314, 334.The non-ferromagnetic amorphous CoHf insertion layer based reader sensorstructures have similar advantages and benefits as shown in theferromagnetic amorphous CoHf insertion layers, in addition to theincreased adhesion and/or increased thermally stability with reducedcorrosion and delamination during post operational processes.

Each of the ferromagnetic layers 312, 332 of the DFL independentlycomprises a material selected from CoB, FeB, CoFeB, CoFe, Co, Fe, NiFe,or other suitable magnetic materials. Each of the plurality offerromagnetic layers 312, 332 has the same or different thicknesses. Forexample, in certain embodiments, each of the plurality of ferromagneticlayers 312, 332 independently has a thickness from about 1.0 nm to about5.0 nm. In certain embodiments, each of the first free layer 310 and thesecond free layer 330 comprises a bilayer, in which each sublayercomprises a material selected from CoB, FeB, and CoFeB and combinationsthereof, in which the amorphous CoHf insertion layer is between thebilayer. For example, FIG. 3 shows the first free layer 310 comprising afirst bilayer 312A-B with a first amorphous CoHf insertion layer 314therebetween and shows the second free layer 330 comprising a secondbilayer 332A-B with a second amorphous CoHf insertion layer 334therebetween. Each of the sublayers of the bilayer has the same ordifferent boron content, such as a sub-layer comprising an atomicpercent of boron (B) from about 5 to about 50% in content. In certainembodiments, the first free layer 310 and the second free layer 330 eachcomprises a bilayer of CoB sub-layers, in which each of the CoBsub-layers independently has an atomic percent of B from about 5 toabout 50% in content.

In certain embodiments, each of the first free layer 310 and the secondfree layer 330 further comprises a ferromagnetic interface layer 313,331 between the respective ferromagnetic layers 312B, 332A and thebarrier layer 320. Each of the ferromagnetic interface layers 313, 331independently comprises CoFe, Co, or Fe. In certain embodiments, each ofthe ferromagnetic interface layers 313, 331 independently comprises CoFewith an atomic percent of Fe from about 5 to about 95% in content. Incertain embodiments, each of the ferromagnetic interface layers 313, 331independently has a thickness from 0.1 nm to about 1.0 nm. Theferromagnetic interface layers 313, 331 are interfacing with the barrierlayer 320 and promote the crystalline texture of the barrier layer 320,such as a barrier layer comprising MgO with (001) crystalline texture.

In certain aspects, the amorphous CoHf insertion layers 314, 334 have asmooth interface for interfacing with the respective ferromagneticlayers 312, 332 providing increased adhesion, reduced delaminationthereof and a higher TMR signal. In certain embodiments, each of theferromagnetic layers 312, 332 and the optional ferromagnetic interfacelayers 313, 331 independently comprises Co or a Co alloy to furtherenhance device performance of the DFL.

The seed layer 302, the buffer layer 304, and the capping layer 308 canbe any suitable material. For example, the ferromagnetic seed layer 302can comprise a ferromagnetic material to functionally act as part of thelower shield S1. Examples of magnetic materials of the seed layer 302include NiFe, CoFe, CoFeB, other magnetic materials, and combinationsthereof. For example, the buffer layer 304 can comprise anon-ferromagnetic material that separates the DFL from the magneticseeds which contacts in turn with the lower shield S1. Examples ofnon-ferromagnetic materials include single or multiple layers of amaterial selected from a list of normal non-magnetic element, such asTa, Ti, Cr, Ru, Hf, Al, Cu, Ag, Au, W, and combinations thereof, such asa buffer layer of Ta/Ru. The barrier layer 320 can comprise anelectrically insulating material of MgO, AlO_(x), TiO_(x), or othersuitable electrically insulating materials. In certain embodiments, thebarrier layer 320 is formed to a thickness of about 1.0 nm or less. Incertain embodiments, the barrier layer is MgO due to the promotion of(001) texture from the optional interface layers 313, 331. The cappinglayer 308 can comprise a non-ferromagnetic material that separates thedual free layer from the upper shield. Examples of non-ferromagneticmaterials include single or multiple layers of a material selected froma list of normal non-magnetic element, such as Ta, Ti, Cr, Ru, Hf, Al,Cu, Ag, Au, W, and combinations thereof, such as a capping layer ofRu/Ta or Ru/Ta/Ru.

FIG. 4 is a schematic illustration of certain embodiments of a magneticelement 400, such as a magnetic element between the shields S1 and S2 ofthe magnetic read head 211 of FIG. 2 or other magnetic read heads, froman MFS view. The magnetic element 400 comprises embodiments of the DFLof the first free layer 310 and the second free layer 330 of magneticelement 300 of FIG. 3 . The magnetic element 400 further comprises abuffer layer 404 and/or a capping layer 408, both comprisingnon-ferromagnetic amorphous CoHf.

In certain embodiments, each of the buffer layer 404 and the cappinglayer 408 is non-ferromagnetic and independently comprises one or moreamorphous forming elements of Ta, Zr, Hf, W, Ti, C, P, B, Si, Nb, othersuitable amorphous forming elements, or combinations thereof alone oralloys with one or more transition metals of Co, Fe, Ni, other suitabletransition metals, or combinations of transition metals thereof. Thebuffer layer 404 and the capping layer 408 independently comprises theone or more amorphous forming elements in an atomic percent content fromabout 30% to about 100%.

In certain embodiments, the buffer layer 404 layer comprisesnon-ferromagnetic CoHf having an atomic percent of Hf from more thanabout 30 to about 95% in content. The buffer layer 404 comprisingnon-ferromagnetic CoHf is an amorphous layer having a highrecrystallization temperature of about 300° C. and above. The bufferlayer 404 comprises a non-ferromagnetic CoHf layer alone or incombination with other non-ferromagnetic layers, such as Ta, Ti, Cr, Ru,Hf, Al, Cu, Ag, Au, W, alloys or multiple layers thereof. In certainembodiments, the buffer layer 404 comprises non-ferromagnetic CoHfforming a high quality and smooth interface with the ferromagnetic layer312A of the first free layer 310.

In certain embodiments, the capping layer 408 comprisesnon-ferromagnetic CoHf with an atomic percent of Hf from more than about30 to about 95% in content. The capping layer 408 comprisingnon-ferromagnetic CoHf is an amorphous layer having a highrecrystallization temperature of about 300° C. and above. The cappinglayer 408 comprises a non-ferromagnetic CoHf layer alone or incombination with other non-ferromagnetic layers, such as Ta, Ti, Cr, Ru,Hf, Al, Cu, Ag, Au, W, alloys or multiple layers thereof. For example,one embodiment of the capping layer 408 is a non-ferromagnetic CoHflayer on the second free layer 330 and a Ru/Ta layer on thenon-ferromagnetic CoHf layer. In certain embodiments, the capping layer408 comprises smooth non-ferromagnetic CoHf forming a high qualityinterface with the ferromagnetic layer 332B of the second free layer330.

In certain aspects, the non-ferromagnetic amorphous CoHf buffer layer404 and the non-ferromagnetic amorphous CoHf capping layer 408 have asmooth interface for interfacing with respective free layers 310, 330providing increased adhesion and/or reduced delamination thereof and/orproviding a higher TMR signal. In certain aspects, the non-ferromagneticamorphous CoHf buffer layer 404 and the capping layer 408 increase thethermal stability of the DFL. In certain embodiments, each of theferromagnetic layers 312, 332 and the optional ferromagnetic interfacelayers 313, 331 independently contains Co to further enhance deviceperformance of the DFL.

FIG. 5 is a schematic illustration of certain embodiments of a magneticelement 500, such as a magnetic element between the shields S1 and S2 ofthe magnetic read head 211 of FIG. 2 or other magnetic read heads, froman MFS view. The magnetic element 500 comprises the embodiments of theDFL of the first free layer 310 and the second free layer 330 ofmagnetic element 300 of FIG. 3 with or without embodiments of the bufferlayer 404 and capping layer 408 of magnetic element 400 of FIG. 4 .

In certain embodiments, the magnetic element 500 further includes a seedlayer 502. The buffer layer 304, 404 is over the seed layer 502. Theseed layer 502 is ferromagnetic and comprises an alloy of one or moretransition metals and one or more amorphous forming elements. Thetransition metal is Co, Fe, Ni, other suitable transition metals, orcombinations thereof. The amorphous forming element is Ta, Zr, Hf, W,Ti, C, P, B, Si, Nb, other suitable amorphous forming element, orcombinations thereof. The seed layer 502 comprises one or more amorphousforming element in an atomic percent in content from more than 0% toless than about 30%.

In certain embodiments, the seed layer 502 comprising a ferromagneticCoHf having an atomic percent of Hf from about 5 to about 30% incontent. The seed layer 502 comprising ferromagnetic CoHf, and is anamorphous layer having a high recrystallization temperature of about300° C. and above. The seed layer 502 comprises a ferromagnetic CoHflayer alone or in combination with other ferromagnetic layers, such asNiFe, CoFe, CoFeB, other ferromagnetic materials, or multiple layersthereof.

In certain aspects, the seed layer 502 has a smooth interface forinterfacing with the buffer layer 304, 404 providing increased adhesionand/or reduced delamination thereof and/or providing a higher TMRsignal. In certain aspects, the seed layer 502 increases the thermalstability of the DFL. In certain embodiments, each of the ferromagneticlayers 312, 332 and the ferromagnetic interface layers 313, 331independently contains Co to further enhance device performance of theDFL.

FIG. 6 is a schematic illustration of a perspective view of certainembodiments of a read sensor 600 including magnetic elements 300, 400,500 of FIG. 3 , FIG. 4 , or FIG. 5 . The read sensor 600 includes twosets 610 of anti-ferromagnetically coupled soft bias (SB) stacks 612A-B(one set is shown in FIG. 6 ) at each side of the magnetic element in across-track direction. The read sensor 600 includes a hard magnet 630located at the rear of the magnetic element. The two sets 610 of SBstacks 612A-B set the easy magnetization direction of the first freelayer 310 about 90 degrees with respect to the easy magnetizationdirection of the second free layer 330. In the presence of a magneticread field, oriented about perpendicular to the plane of the MFS, themagnetization directions move to be either more parallel to one anotheraway from the MFS or more antiparallel toward the MFS. As themagnetization directions become more parallel to one another theelectrical resistance of the sensor decreases. As the magnetizationdirections become closer to antiparallel to one another, the electricalresistance of the sensor increases. The hard magnet 630 provides a hardbias so that the magnetic response of the sensor is within or near alinear region of the transfer curve. In other embodiments, the magneticelements 300, 400, 500 can be shaped and incorporated with other softbias and/or hard bias elements to form a read sensor. In otherembodiments, the magnetization directions of the DFL can be setnon-symmetrically.

The magnetic elements 300, 400, 500 of FIG. 3 , FIG. 4 , or FIG. 5 aredescribed herein as comprising a “layer.” It is understood that as usedherein, the term “layer” means a single layer or multiple sub-layers.For example, a metal alloy layer can be one or more sub-layerscomprising a metal alloy, can be multiple sub-layers of single metals,or combinations thereof. Although some of the embodiments are describedin reference to a DFL device, in other embodiments, the insertionlayers, buffer layers, capping layers, and seed layers can be applicableto a single free layer device. Although the some embodiments aredescried in reference to a TMR device, in other embodiments, the freelayers, insertion layers, buffer layers, capping layers, and seed layerscan be applicable to giant magnetoresistive (GMR) devices as well.

In certain embodiments, amorphous insertion layers (e.g., CoHf) betweenbilayer free layers (FLs) of dual free layer (DFL) reader sensorsprovide higher TMR signal, increased magnetic moment (Mst), high TMRsignal-to-noise (SNR), and/or low magnetostriction. The amorphousinsertion layers (e.g., CoHf) can be ferromagnetic in certainembodiments or can be non-ferromagnetic in certain embodiments. Incertain embodiments, a non-ferromagnetic amorphous buffer layer (e.g.,CoHf) and/or a non-ferromagnetic amorphous capping layer (e.g., CoHf)has a smooth interface for interfacing with the film layers of themagnetic elements providing increased adhesion and/or reduceddelamination thereof and/or providing a higher TMR signal. In certainembodiments, a ferromagnetic amorphous seed layer (e.g., CoHf) has asmooth interface for interfacing with the film layers of the magneticelements providing increased adhesion and/or reduced delaminationthereof and/or providing a higher TMR signal. In certain aspects, theamorphous layer(s) (e.g., CoHf) has a high recrystallization temperatureof about 300° C. and above, providing thermal stability to the magneticelement.

In one embodiment, a magnetic element includes a first free layer, abarrier layer, and a second free layer. The first free layer includes afirst ferromagnetic bilayer selected from CoB, CoFeB, FeB, andcombinations thereof and a first amorphous insertion layer between thefirst ferromagnetic bilayer. The barrier layer is over the first freelayer. The second free layer is over the barrier layer. The second freelayer includes a second ferromagnetic bilayer selected from CoB, CoFeB,FeB, and combinations thereof and a second amorphous insertion layerbetween the second ferromagnetic bilayer. Each of the first and secondamorphous insertion layers independently has a recrystallizationtemperature of about 300° C. and above.

In another embodiment, a magnetic element includes a buffer layer, afirst free layer, a barrier layer, a second free layer, and a cappinglayer. The buffer layer includes a first non-ferromagnetic layer. Thefirst free layer is over the buffer layer. The first free layer includesa first ferromagnetic bilayer selected from CoB, CoFeB, FeB, andcombinations thereof and a first amorphous insertion layer between thefirst ferromagnetic bilayer. The barrier layer is over the first freelayer. The second free layer is over the barrier layer. The second freelayer includes a second ferromagnetic bilayer selected from CoB, CoFeB,FeB, and combinations thereof; and a second amorphous insertion layerbetween the second ferromagnetic bilayer. The capping layer is over thesecond free layer. The capping layer includes a second non-ferromagneticlayer. Each of the first and second amorphous insertion layersindependently has a recrystallization temperature of about 300° C. andabove.

In still another embodiment, a magnetic element includes a ferromagneticseed layer, a non-ferromagnetic buffer layer, a first free layer, abarrier layer, a second free layer, and a capping layer. Thenon-ferromagnetic buffer layer is over the ferromagnetic seed layer. Thefirst free layer is over the buffer layer. The first free layer includesa first ferromagnetic bilayer selected from CoB, CoFeB, FeB, andcombinations thereof and a first amorphous insertion layer between thefirst ferromagnetic bilayer. The barrier layer is over the first freelayer. The second free layer is over the barrier layer. The second freelayer includes a second ferromagnetic bilayer selected from CoB, CoFeB,FeB, and combinations thereof and a second amorphous insertion layerbetween the second ferromagnetic bilayer. The capping layer is over thesecond free layer. The capping layer includes a non-ferromagnetic layer.Each of the first and second amorphous insertion layers independentlyhas a recrystallization temperatures of about 300° C. and above.

EXAMPLES

The Examples are not meant to limit the scope of the claims unlessexpressly recited as part of the claims.

Example 1

The coercivity Hc (Oe) was measured of samples of various free layerstacks or film layers after a series of short thermal annealing for oneminute at various temperature and plotted in FIG. 7 .

Sample 701 was a multilayer structure free layer of CoFe(B)/NiFe. Sample702 was a single CoB free layer having about 20 atomic percent of B incontent. Sample 703 was a single Co(Fe)B free layer having about 10 to60 atomic percent of Fe and about 20 atomic percent of B in content.Sample 704 included a single magnetic CoHf free layer having a thicknessof 7.5 nm and containing about 10 atomic percent of Hf in content.Sample 705 included a single magnetic CoHf free layer having a thicknessof 7.5 nm and containing about 20 atomic percent of Hf in content.

All of the samples, except sample 701, showed that their free layerstacks were amorphous with low coercivity as deposited. All of thesamples showed that each of the free layer stacks was thermally stableand continued to be with low coercivity at anneal temperatures of lessthan 300° C.

Sample 701 of the multilayer structure free layer with a majority ofcrystallization became thermally unstable and continued to increase incoercivity with anneal temperatures ramped up above 200° C.

Sample 702 of the ferromagnetic amorphous CoB free layer and Sample 703of the ferromagnetic amorphous Co(Fe)B free layer showed that each ofthe free layers became thermally unstable and crystallized rapidly withsubstantially increased coercivity at anneal temperatures from about300° C. to about 400° C.

Sample 704 of the ferromagnetic amorphous CoHf free layer having about10 atomic percent of Hf in content showed that the free layer wasthermally stable and continued to be amorphous mostly with lowcoercivity at anneal temperatures from about 300° C. to about 400° C.

Sample 705 of the ferromagnetic amorphous CoHf free layer having about20 atomic percent of Hf in content showed that the free layer wasthermally stable and continued to be amorphous with low coercivity atanneal temperatures from about 300° C. to about 400° C. Theferromagnetic amorphous CoHf20 layer unexpectedly showed a decrease incoercivity at anneal temperatures from about 300° C. to about 400° C.One skilled in the art would have predicted that the coercivity would beabout the same or higher at anneal temperatures from about 300° C. toabout 400° C., but would also got decreased if there occurred adispersion in anisotropies that should not be a measure of thermalstability in origin as described above.

Coercivity is the amount of force required to rotate the magneticdomains of a ferromagnetic material. It shows a property of increasingrapidly with gradual or fast recrystallization of amorphous materials. Amaterial with low coercivity that is stable at various annealtemperatures shows that the material has good reliability for use in afree layer due to its thermal stability. The ferromagnetic amorphousCoHf layers stabilized the coercivity and/or delayed the progress andprocess of crystallization at anneal temperatures from about 300° C. toabout 400° C.

Example 2

The magnetic moment Ms (emu/cc) and magnetostriction MS (ppm) weremeasured for various samples of the ferromagnetic amorphous CoHf freelayer with various atomic percent of Hf from zero up to about 25% incontent and plotted on the chart of FIG. 8 .

The samples showed that the amorphous CoHf layers were ferromagneticwith zero to 30 atomic percent (estimated) of Hf in content. Magneticmoment diminished at about 30 atomic percent of Hf in content. Theamorphous CoHf layers with 30 atomic percent (estimated) of Hf andgreater in content were non-ferromagnetic with a zero magnetic moment.

The samples showed that the CoHf layers had a very large negativemagnetostriction with an Hf content of less than about 5 atomic percent,similar as shown in cobalt films. The samples showed that theferromagnetic amorphous CoHf layers had a small positivemagnetostriction with an Hf content of about 5 atomic percent andgreater.

Example 3

The effective magnetic moment (Meff, in emu/cc) and the damping constant(alpha) of various samples were measured by FMR with the applied fieldin the plane of a film over various normalized Hf thicknesses of theferromagnetic amorphous CoHf insertion layer as shown in FIGS. 9A and9B. The normalized Hf thickness of the ferromagnetic amorphous CoHfinsertion layers is the measured CoHf layer thickness times the Hfcontent in atomic percentage. It described the magnetic properties andtheir changes with the ferromagnetic amorphous CoHf insertion layershaving increasing Hf content or decreasing magnetic moment. Samples 901and Samples 902 each comprised a dual free layer structure as shown inFIGS. 3 and 4 . Samples 901 further included a buffer layer of anon-ferromagnetic stack of Ta/Ru and a capping layering of anon-ferromagnetic stack of Ru/Ta. Samples 902 further included a bufferlayer of non-ferromagnetic amorphous CoHf and a first capping layer ofnon-ferromagnetic amorphous CoHf combined with a second capping layer ofRu/Ta.

In the set of Samples 901 and 902, magnetic moment showed to increase byabout 10% in the free layers and dual free layer structures irrespectiveof the insertion of ferromagnetic amorphous CoHf layer in the freelayers, with non-ferromagnetic amorphous CoHf buffer and capping ascompared to those having crystalline Ta/Ru buffers and capping layers.The measured values of the effective magnetic moment from FMR werefairly close to those obtained from static magnetic measurements ofmagnetization of the free layers. The enhancement of magnetic moment wasclosely associated with possible migration or redistribution of boronelement within and/or across those sublayers of the free layerscontaining Co(Fe)B. In Samples 902, the non-ferromagnetic amorphous CoHfbuffer and capping layer sandwiched the entire core structures of dualfree layers, providing a kind of sink for boron element to redistributeout of the free layers and that helped increase magnetic moment of thefree layers. This was similar in effect as observed in the examples inFIG. 8 , in which the magnetic moment of CoHf layers was diluted againstthe increasing content of Hf or enhanced with the decreasing content ofHf. In Samples 902, the measured values of the effective magnetic momentshowed to decrease slightly as the normalized Hf thickness of theferromagnetic amorphous CoHf insertion layer or the content of Hf wasincreased due to such effects of dilution. These effects were howevernot appreciably evident in Samples 901 with the crystalline Ta/Ru bufferand capping layer.

In comparison to Samples 901, Samples 902 showed lower dampingconstants. This indicated non-ferromagnetic amorphous CoHf buffer andcapping layer yielded smaller damping constant as compared with Ta/Rubuffer layer and Ru/Ta capping layer. Samples 902 were featured withtheir dual free layer structures more coherently grown and textured,robustly integrated, and more thermally stable. The reducedinhomogeneities in local or layer structures would contribute to adecrease in the half peak width in resonance, and then the dampingconstant of the dual free layers. Following the relationship thatdescribes magnetic signal-to-noise ratio (SNR) of a read sensor, SNR isproportional to the root square of the ratio of the (effective) magneticmoment to the damping constant in DFL devices. Devices formed fromSamples 902 would deliver higher magnetic SNR than devices formed fromSamples 901.

Example 4

TMR ratio (%), magnetic moment Mst, and coercivity Hc in devices with aresistance area of about 0.4 Ωμm² were measured for different DFL readersensors as shown in FIGS. 10A-10B. Sample 1001 was the baselined CoBbilayer DFL with CoFe interface layers to the barrier layer. Sample 1002was the CoB bilayer DFL having CoFe interface layers to the barrierlayer, ferromagnetic amorphous CoHf insertion layers between the CoBbilayers, a crystalline Ta/Ru buffer layer, and a crystalline Ru/Tacapping layer (refer to FIG. 3 ). Sample 1003 was a CoB bilayer DFLshaving CoFe interface layers to the barrier layer, ferromagneticamorphous CoHf insertion layers between the CoB bilayers, anon-ferromagnetic amorphous CoHf buffer layer, and a non-ferromagneticamorphous CoHf capping layer combined with a second crystalline Ru/Tacapping layer (refer to FIG. 4 ). Sample 1003 showed still higher TMRratio (%) signal than Sample 1002 which showed higher TMR (%) signalthan sample 1001. Sample 1001 to 1003 were with adjustable and lowdevice magnetostriction at about +5.0 ppm and less for the dual freelayer structures.

In comparison to Sample 1001, Sample 1002 and Sample 1003 (andvariations thereof) were more coherently grown and textured, robustlyintegrated, and more thermally stable. These samples outperformed Sample1001 in general in magnetic properties of the free layers, in additionto their increased thermal stability and process robustness againstcorrosion. In the set of Sample 1001 to 1003, magnetic coercivity Hcshowed to decrease in the free layers and dual free layer structureswith ferromagnetic amorphous CoHf insertion layers in the free layers.The reduction of Hc is significant, and the measured Hc of less than 4Oe is fairly close to those values of 3.5-4.5 Oe from standard softmagnetic NiFe materials. The magnetic moment in the dual free layerstructures showed similar but somewhat smaller in Sample 1002 than inSample 1001. This quantity in Sample 1003 however showed to increase by8.0% when it is compared to Sample 1001, or by 10.0% when compared toSample 1002 similarly with the ferromagnetic amorphous CoHf insertionlayers in the free layers.

In Sample 1003, the output amplitude showed to increase by almost halfas compared to Sample 1001, given that TMR ratio (%) in device increasedby about 10%. This unproportioned enhancement in amplitude was in partclosely related to coherent texture in dual free layer structures,robust/integrated device structures and increased thermal stability andprocess robustness against corrosion. In addition, it was in partattributed to increased reader sensor stabilization due to overalloptimized and/or balanced magnetic properties in the dual free layerstructures, and due the provided/additional flexibility and mechanism ofadjustable interlayer coupling between sublayers in the free layers.Consequently Sample 1003 provided higher field sensitivity, and QSNR. Inquasi-static magnetic test, Sample 1002 showed increased performance or1.0 dB gain, while Sample 1003 outstood and demonstrated roughly 2.0 dBgain over the baseline process or Sample 1001, or 1.0 dB gain overSample 1002 in QSNR.

While the foregoing is directed to embodiments of the presentdisclosure, other and further embodiments of the disclosure may bedevised without departing from the basic scope thereof, and the scopethereof is determined by the claims that follow.

What is claimed is:
 1. A magnetic element, comprising: a free layer, thefree layer comprising: a ferromagnetic bilayer selected from CoB, CoFeB,FeB, and combinations thereof; and an amorphous insertion layer betweenthe ferromagnetic bilayer; and a barrier layer over the free layer,wherein the amorphous insertion layer has a recrystallizationtemperature of about 300° C. and above.
 2. The magnetic element of claim1, wherein the free layer further comprises a ferromagnetic interfacelayer interfacing the barrier layer and the ferromagnetic bilayer,wherein the ferromagnetic interface layer comprises a material selectedfrom CoFe, Co, and Fe.
 3. The magnetic element of claim 1, wherein theamorphous insertion layer is a ferromagnetic material comprising: analloy of one or more transition metals of Co, Fe, Ni, other transitionmetals, or one or more combinations thereof with one or more amorphousforming elements of Ta, Zr, Hf, W, Ti, C, P, B, Si, Nb, or one or morecombinations thereof, wherein the alloy comprises the one or moreamorphous forming elements from more than 0 atomic percent to less than30 atomic percent in content.
 4. The magnetic element of claim 3,wherein the amorphous insertion layer is CoHf having an atomic percentof Hf from about 5 to about 30%.
 5. The magnetic element of claim 1,wherein the amorphous insertion layer is non-ferromagnetic and comprisesan amorphous material selected from a group consisting of Ta, Zr, Hf, W,Ti, C, P, B, Si, Nb, multiple layers thereof, and alloys thereof.
 6. Themagnetic element of claim 5, wherein: the amorphous insertion layer is anon-ferromagnetic amorphous material comprising: one or more amorphousforming elements of Ta, Zr, Hf, W, Ti, C, P, B, Si, Nb, or one or morecombinations thereof alone, or an alloy of Co, Fe, Ni, or one or morecombinations thereof, wherein the amorphous insertion layer comprisesthe one or more amorphous forming elements from about 30 atomic percentto about 100 atomic percent in content.
 7. The magnetic element of claim6, wherein the amorphous insertion layer is CoHf having an atomicpercent of Hf from more than about 30 to about 95% in content.
 8. Themagnetic element of claim 1, wherein the barrier layer is MgO.
 9. Themagnetic element of claim 1, wherein the free layer is proximate abuffer layer and has a magnetostriction of about 5.0 ppm or less andwherein the magnetic element has an overall magnetostriction of lessthan 5.0 ppm.
 10. A magnetic media drive comprising a read sensorcomprising the magnetic element of claim
 1. 11. A magnetic element,comprising: a buffer layer comprising a first non-ferromagnetic layer; afree layer over the buffer layer, the free layer comprising: aferromagnetic bilayer selected from CoB, CoFeB, FeB, and combinationsthereof; and an amorphous insertion layer between the ferromagneticbilayer; a barrier layer over the free layer; and a capping layer overthe free layer, the capping layer comprising a second non-ferromagneticlayer, wherein the amorphous insertion layer has a recrystallizationtemperature of about 300° C. and above.
 12. The magnetic element ofclaim 11, wherein each of the first non-ferromagnetic layer of thebuffer layer and the second non-ferromagnetic layer of the capping layeris independently a crystalline material selected from a group consistingof Ta, Ti, Cr, Ru, Hf, Al, Cu, Ag, Au, W, alloys thereof, and multiplelayers thereof.
 13. The magnetic element of claim 11, wherein each ofthe first non-ferromagnetic layer of the buffer layer and the secondnon-ferromagnetic layer of the capping layer independently comprises anamorphous material selected from a group consisting of Ta, Zr, Hf, W,Ti, C, P, B, Si, Nb, combinations thereof, and alloys thereof.
 14. Themagnetic element of claim 13, wherein each of the firstnon-ferromagnetic layer of the buffer layer and the secondnon-ferromagnetic layer of the capping layer independently is anamorphous material comprising: an alloy of one or more transition metalsof Co, Fe, Ni, other transition metals or one or more combinationsthereof with one or more amorphous forming elements of Ta, Zr, Hf, W,Ti, C, P, B, Si, Nb, or one or more combinations thereof, wherein theamorphous material comprises the one or more amorphous forming elementsfrom 30 atomic percent to about 100 atomic percent in content.
 15. Themagnetic element of claim 14, wherein the buffer layer and the cappinglayer each independently comprises CoHf having an atomic percent of Hffrom more than about 30 to about 95% in content, wherein the cappinglayer comprises a non-ferromagnetic amorphous CoHf layer alone or incombination with a Ru/Ta or Ru/Ta/Ru layer on the non-ferromagneticamorphous CoHf layer.
 16. A magnetic media drive comprising a readsensor comprising the magnetic element of claim
 11. 17. A magneticelement, comprising: a ferromagnetic seed layer; a non-ferromagneticbuffer layer over the ferromagnetic seed layer; a free layer over thenon-ferromagnetic buffer layer, the free layer comprising: aferromagnetic bilayer selected from CoB, CoFeB, FeB, and combinationsthereof; and a first amorphous insertion layer between the ferromagneticbilayer; a barrier layer over the free layer; and a capping layer overthe free layer, the capping layer comprising a non-ferromagnetic layer,wherein the amorphous insertion layer has a recrystallizationtemperature of about 300° C. and above.
 18. The magnetic element ofclaim 17, wherein the ferromagnetic seed layer comprises at least onelayer of a crystalline material selected from a group consisting oftransition metal Co, Fe, Ni, other suitable transition metals,combinations thereof, and alloys thereof.
 19. The magnetic element ofclaim 17, wherein the ferromagnetic seed layer is an amorphous materialcomprising an alloy of one or more transition metals of Co, Fe, Ni,other suitable transition metals, or one or more combinations thereofwith one or more amorphous forming elements of Ta, Zr, Hf, W, Ti, C, P,B, Si, Nb, or one or more combinations thereof, wherein the alloycomprises the one or more amorphous forming elements from more than 0atomic percent to less than 30 atomic percent in content.
 20. Themagnetic element of claim 17, wherein the ferromagnetic seed layercomprises at least one layer of a crystalline material selected from agroup consisting of Co, Fe, Ni, and alloys thereof and at least onelayer of an amorphous material comprising an alloy of one or moretransition metals of Co, Fe, Ni, other suitable transition metals, orone or more combinations thereof with one or more amorphous formingelements of Ta, Zr, Hf, W, Ti, C, P, B, Si, Nb, or one or morecombinations thereof, the alloy comprising the one or more amorphousforming elements from more than 0 atomic percent to less than 30 atomicpercent in content.
 21. The magnetic element of claim 17, wherein theferromagnetic seed layer comprises CoHf having an atomic percent of Hffrom about 5 to about 30% in content.
 22. A magnetic media drivecomprising a read sensor comprising the magnetic element of claim 17.